Spills of fuels, oils, hydraulic fluids, solvents and other flammable liquids are common in the course of equipment maintenance procedures, refueling operations, and accidents involving vehicle collisions or roll overs. A great variety of absorbent materials have been used to soak up such spilled flammable liquids. Both organic and inorganic absorbents have been commonly used for that purpose. Useful organic absorbents include sawdust, wood pulp, paper, peanut hulls, ground corn cobs, shredded peat moss and other cellulosic materials. Commonly used inorganic absorbents include clays pumice, expanded micas, diatomaceous earth, fullers earth and many more. U.S. Pat. No. 4,537,877, to Ericsson, presents a comprehensive description of organic and inorganic solid absorbents and sets out the advantages and disadvantages of the various materials.
Adsorbent solids have also been used to treat spills of many common hydrocarbon solvents and fuels. One such adsorbent is sold under the trademark SPILL-X and is described in U.S. Pat. No. 4,770,715. The adsorbent composition comprises activated carbon either alone or compounded with clays, low molecular weight hydrophobic polymers, alumina, silica, magnesium silicate, and similar materials. An application technique taught in the patent is to apply the absorbent in layers; a first layer to absorb the spill followed by one or more other layers which serve to elevate the flashpoint of the absorbed liquid.
It is also known to use a mixture of sawdust and particulate rubber, typically a high molecular weight polyisobutylene, to absorb hydrocarbon liquids. The rubber particles tend to dissolve in the hydrocarbon liquid as it soaks into the sawdust particles to form an adhesive which binds the liquid-loaded sawdust particles together. In practice, it has been found that the adhesive properties of the liquid-loaded composition tends to cause it to adhere to surfaces such as concrete floors thus complicating the clean-up effort.
Applicant, in his prior U.S. Pat. No. 5,062,996, described methods and compositions for sorbing flammable liquids to render the resulting product fire resistant. Those compositions necessarily included three components. A first necessary component comprised an absorbent solid or mixture of absorbent solids, those absorbents preferably being inorganic and non-combustible. A second necessary component comprised a polymer, such as a rubber, which is soluble in the liquid being sorbed, and of a high enough molecular weight to impart a substantial degree of viscoelasticity to the liquid. The last necessary component comprised one or more dry chemical fire extinguishing agents such as, for example, sodium bicarbonate and monoammonium phosphate.